Help, car backfires, stutters, and cuts off at 6k with 4b.
Help, car backfires, stutters, and cuts off at 6k with 4b.
I took my turbo ITR to a dyno for some tuning. It has 4b with a p28. After some tuning at idle, the car ran decent, until it reved around 5k-6k. It would then dump fuel and stutter barely making it into higher revs. My tuner though that maybe the rev limiter was set too low. He tried to raise the rev limit with the button, but couldnt get it to work. We switched boxes to a stage 2, and were able to set the revs via the button, but coudnt get it to work on the 4b. We then tried to run it a couple more times, and actually got the car to rev to nearly 8k. After a couple more runs, it went back to the 5k-6k stuuter. Does anyone know what is going on? My tuner recommended that I upgrade to s200 because 4b is outdated, and that it should take care of the problem. I bought 4b a year and a half ago before the rebuild of my motor, and really dont want to spend extra money on something I just bought. Thaks for any input guys.
Unplug the 3 step (if it has 3 step). And reset the stage4 box by holding down the puch button which you switch on the ignition. The rev limiter should now be at 8500 rpm. Check the fuel and ignition tables used in the ROM and make sure the ignition under boost look reasonable and the fuel table rise in a linear curve. You can post the ROM for us to look at if in doubt.
Test for the misfire. If it is still present then chances are that it is ignition related (how much boost are you running at 5000 rpm?). You can hold the waste gate open (internal wastegates - use a bit of welding wire to hold the valve open, external wastegates - take the top of the diaphram off and allow the valve to pop open). The engine should then make no more than 1 lb boost (otherwise you have boost creep). Test for the misfire again. If it goes away then there is a good chance the problem is ignition related. You can also try gapping the plugs down to see if that helps.
Test for the misfire. If it is still present then chances are that it is ignition related (how much boost are you running at 5000 rpm?). You can hold the waste gate open (internal wastegates - use a bit of welding wire to hold the valve open, external wastegates - take the top of the diaphram off and allow the valve to pop open). The engine should then make no more than 1 lb boost (otherwise you have boost creep). Test for the misfire again. If it goes away then there is a good chance the problem is ignition related. You can also try gapping the plugs down to see if that helps.
Hondata